Process of producing endothermic gas reactions and apparatus therefor.



H. GROH MANN. NDOTHERMIG GAS REACTIONS AND APPARA APPLICATION FILED AUG.19,1911.

TUS THEREFOR PRDGESS 0F PRODUCING E 9M 1 no 1 0 .2 H A d 8 t H 8 m P.

UN sTA'rEs PATENT OFFICE;

vHANS 'GBOHMANN, OF COLOGNE, GERMANY, ASSIGNOB TO THE F131! 01 SLPETER- SKUBE-INDUSTRIE-GESELLSCHAFT, G. M. B. 11., OF COLOGNE, GERMANY Process 02 rnonucmo ENno'rHEmaIc oAs REACTIONS nn ArrAnA'ros mnnnroa.

To all whom it may concern: a

1 Be it known that I, HANsGRonMANN, a subject of the King lolc-gne-cn-the-Rhine, in the Kingdom of Prussia and German Empi re, have nvented new and useful Improvements in Processes of Producing Endothermic Gas Reactions and Apparatus Therefor, of which the,fol-' lowing is a specification.

The formationcof nitrogen oxids from air by, means of the electric arc is, the resent time, considered to. be due to the t ermic action of the are. It is commonly understood that in order to combine atmospheric nitrogen with oxygemit is necessary to heat the air to a certain temperature, with the reatest care-to avoid loss of heat, then to eeplsaid air at this temperature for some time, until the condition of reaction equilibrium is obtained, and finally to cool the hotgases. down to about 1500 C more, quickly than the decomposition of nitrogen oxids can take placeat the temperature in question. In this way the eatest ouput is believed to-be obtained at t e tempera ure chosen. A

This inverition relates to processes of pro} ducing' endothermic gas reactions and ap? paratus therefor; and it'comprises a'p'rocess whreina gas or a mixture of gases to'be Y treated is caused to travel as a moving tubularcenvclop or mantle of relatively small I are; and it also comprisesa paratus suit-V diameter in contact with and laterally inclosing an elongated electric arc, sprung'betwcen a pair of suitably energized electrodes in a reaction chamber, another gaseous tubuthe alr is heated with the greatest economy larr envelop or mantle of greater diameter is caused to-travel outside of and substantially coaxially with the first named envelop but spaced away therefrom throughout the major portion ofits travel by an intermediate layer of relatively quiet gas, and the gases issuing from the reaction chamber in close proximity to the arc and relatively rich in reaction products are cooled separately from the relatively dilute gases issuing from the chambh-at a greater distance from the able for carrying out the sai process, said apparatus comprising a shaft furnace, means -for maintaininga long stable arc in the. fur- .nace shaft, means for conducting a bodyof;

gas alon and in close proximity to the arc and in t e approximate form of a hollow 5V5 cylindrical mantle or envelop, means'for 0 m 5 Specification of Letters Patent. Application m 41 m 10, 1011. Serial 10.144329;

of Prussia, residing at.

Patented Aug. 20, 1912.

ducting another gaseous envelop outside of the first named envelop and close to the of nitrogenoxids.

- Almost all forms of apparatus heretofore proposed only partly com'ly with these theoretical requirements. proposed devices, a comparatively small part of the total amount of air conducted to the bfi' direct contact with the arc,'while the s bsequent cooling is effected by mixing the hot reaction gases with the cold part of the air first introduced, or with separately introducedcold air. A definite temperature and aperfect utilization of the reaction 'cannot be obtained under these conditions, because means of cooled capillaries than is obtained technically.

In the apparatus of the present invention possible, while at the same time a very high reacting temperature is used. Furthermore, advantage is taken of the principle that subjecting the hot reaction gases to the influence of cooled metal surfaces not only qualihigher yield'of nitrogen oxids than accordmg to the method of cooling heretofore With'cold air.

In the drawing illustrating the invention shown b way. of example. The furnace ,bodyof re brick or suitable refractory material. 15 incloses a shaft whose walls 16 disha tageherall conical'form. :Between the 'clectrodesla 2 a quietlyburning vertical walls of the furnace shaft, and means for a manner as to effect the desired formation n some of the,

furnace is heated to a very high temperature from every flame heretofore used a much, higher concentration can be produced by tatively but also quantitatively gives a adopted by mixing the hot reactiongases a vertical section'of a cylindrical'furnace is i yer e from below upward, thus giving the arc is formed. The electrode l at the inlet end of the shaft is" isolated by cylinder 3,

of porcelain or. the like from the nozzle body 4 having annular openings concentric tothe axis of the furnace. Connected to the nozzle body 4 is tube or twyer 13 to which air under pressure is led through '14. The air issuing from the inner nozzle forms substantially a hollow oyli der, and the air from the outer nozzle, :1 ollow cone. The

outer needs has substantially the same conicit from axis of the electrodes, as shown in the drawing. The temperature andvolume of the air increase in the direction 1, 2. Atthe .top'or outlet end the shaftwalls converge or curve inwardly somewhat and the couicity of the shaftpasses over gradually into annular bod 5 0 highly .re-

ractory material surrounded by an outer 'ring 5, by which the current of air issuing nfrom the inner nozzlefopening and surrounding the arc is contracted. A cooling device 6 located beyond theconjracted portion of the furnace shaft has concentric-annular slits or passages T and 8 through which the gases cave the fur ace shafta Thc cooling box 6,

which is best constructed of meta-l," is supplied with a suittlblel cooling medium, such as water. through pipe 10, the cooling 7 mediumbeing'led oil through outlet pipe This straightening tendency of an annular nozzle. having an inner diameter 1' larger;

l2.v In the interior ot the shaft ismaiir' than the diameter 1* of the electrodes, is so decisive that even in-the open air stable arcs of any desired length can be formed. The outer envelop B issues" from the outer annular nozzle opening and passes along'the shaft walls; The inner current or envelop is separated frorn the outer on'e'by' a gaseous has comparatively little mo- This intermediate zone protects thezone C which tion. gases lmmediately surrounding the are from excessive lossesof heat; so that the ternperature of these gases surrounding the are can bedriven verv high and nrraduallv in- The gaseous e furnace shaftcreases from 1. toward mantles thus pass throughth suh tantiallv' independently of emjzh other. The air blown along the Wall. out of the outer annular nozzle opening serves to abas the flame shaft, diverging awaythe furnace I of these more or less definite gaseouszones of the gases in the upper part oftheshaft I v due to the higher-temperature there existing;

conversion of the 'oxids than occurs in the body of gases passsorb the heatradiating from the arc, and, with the assistance of the annular member 5, to contract the mantle of ases immediately surrounding the are at the top, so that these gascs pass out mainly th'roughthe annular passage 7, while the outer gaseous current asses mainlythrough the passage 8. The amount of air issuing from the'outer nozzle opening at the lower end of the shaft. should be so regulated thatthe, temperature of the outer zone B in'the vicinity of the annular body 5 is-just below the melting temperature of said body. f i The contraction of the top end of the shaft is desirable in order to decrease the loss of heat by radiation in the cooling device a'nd, further, also for the purpose of causing the change from high temperature to a lower temperature to take place as suddenly aspossible. If the contraction were effected with the hot gases immediately sur-- rounding the are directly. in contact with tlge shaft walls and Without conducting a shielding and spacing layer of cooler gases along the ivalh the temperature of the air immediately surrounding the arc could not be driven so high, because otherwise the material of-the annular body 5 would sufi'er. The boundaries of. the various gaseous zones or envelops are indicated on the drawing by dotted lines. It is to be understood however that such boundaries are not rigidly defined. and that the drawing represents such boundaries onlya-pnroximately- The diverging character of the major part of shaft permits the maintenancev or mantles in spite of the increasing volume,

havinsr difierent speeds of motion require considerable time to become mixed. Consequently most of the air led along the wall to protect theannular body 5 and not having a. very high temperature reallv passes through the annular passage 8. while most of the gases traveling close to the arc pass through the annular passage 7. Ti. both 'bodiesof gas were led. off through one-passage a. certain decomposition of the formedfni'troa'en oxids would occur; ow ng to the'lhlsllfilcltni cooling-etl'ected by the intimate m xture of the very hot gases immediatelysurrounding the are and those of lower :temperaturesj passing along the Wall of the shaft and the consequent partial forming-reaction.

In the: gases traveling close to the are there is of course a considerably higher original air into nitrogen Consequently ing along the shaft walls.

"the'gqses leaving the furnace shaft through high concenpassage 7' are of relatively 105. Tt 1s a well known phenomenon that-gases reversal 0f. the oxid- -tratcd" and the dilute gases oxid-forming reaction. The

inasp'ra tration as regards their oxids, while those leaving through passage 8 are relatively dilute. Both the concenare suddenly cooled by'themetal surfaces in cooling box 6 to a temperature atwhich nitrogen oxids are 'stable. Consequently when the coo gases mingle ,-,in chamber 9 there is substantiallyno loss ofoxids by reversal of the uses are led from chamber 9 toxany convenient place for suitable treatment I If it is desired" to separately collect the gases of higheiconcentraticn from the passage 7 it is only necessary to divide the chamber 9 intotwo parts, into one of which pass the gases from the assage 7 and into the other part the gases mm the passage 8. What I claim and desire to secure by Let'- ters Patent of-the United States is 1. A furnace forproducmg endothermic gas reactions, comprising in combination electrodes for producing an electric are, an annular: air nozzle surrounding, and concentric to one of said electrodes, an annular gas nozzle' surrounding said first nozzle and diverging away from the axis of said electrode, [pear-shaped shaft inclosing the space between said electrodes, substantially as, and for the purpose, set forth.

2; A' furnace for producing endothermic gas reactionm' comprisingin combination, electrodes for producing an electric are, an nularflgas nozzlessurrounding, and directed at di erent angles in regard. to,vsai.d electrodes,= a pear-shaped jshaftr inclosing the space between saidelectrodes, and concentric passages provided at' the end of said shaft opposite to that at which the nozzles are provided substantially as, and for the purpose, set orth. v

3. A furnace for producing endothermic gas, reactions, comprising electrodes for producing a electricarc, gas nozzles surrounding, an at different an: gles to, one of said elect es, an internally pear shaped, shaft inclosing the space be-' tween said electrodedpassages concentric to the axis at said electrodes and disposed at the end f; said} shaft opposite to-that at which th nozzles are disposed, and water jackets td cool said passages, substantially as, and'fcr the purpose, set forth.

4. A furnace for producing endothermic gas reactions, comprising'a fu ace shaft relatively narrow at one end and having walls which diverge gradually toward' the opposite end of said shaft and then converge somewhat abruptly near said opposite end,

an electrode located at each end of said shaft and substantially axially thereof, means for passing a gas through axis, and means for passing a gas shaft walls.

5. A furnace along the for producing endothermic c'r'mtent of nitrogen verge somewhat abruptly led in combination,

said shaft close to its gas reactions, comprising a furnace shaft relatively narrow at one end and hav ng walls which diverge gradually toward the opposite end of said shaft and then connear said opposite end, an electrode locate at each end of said shaft and substantially axially thereof, means for passing a-gas through said shaft close to its axis, means' for passing a gas along the shaft walls, and means: for separately coolg g s which have passed axially through the shaft and those which have passed through the shaft near its walls.

6. furnace for producing endothermic gas reactions; comprising a furnace shaft having suitable refractory walls, means for maintaining an arc in said shaft, means for passing a mantle or envelop of gas throu h said shaft close to the arc, and means or passing another mantle or envelop of gas along the shaft walls' independently of the first-named mantle.

7, A furnace for producing'uendothermic gas reactions, comprising a rnace shaft, means for maintaining an are substantially axially thereof, and .Iheans for passing through said shaft spacedand substantially concentric envelops or mantles of as surrounding the arc and traveling in t e same general direction. 8. The process of producing endothermic gas reactions, which a body of gases to b'e treated along and in close proximity being substantially in the form of a hollow cylindrical envelop or mantle of traveling gases laterally inclosing said are, conductin another gaseous mantle in the same genera direction but outside of; the mantle first named and substantially distinct therefrom, and separately cooling the gases of the said mantles after they have passed beyond the arc. v 1

9. The proces of producing endothermic gas reactions, which comprises establishing a long are in a suitable furnace chamber and conducting through said chamber a plurality of spaced mantles of gases to be treated traveling in the samegeneral direction,

said mantles inclosmg laterally and being substantially coaxial with said are, and the comprises conducting innermost of said mantles being close proximity to said are.

10. The process of producing oxids of nitrogen, 'hich comprises conducting gases comprising nitro en in the formof a traveling mantle along proximity to an electric arc, and maintaining another mantle of gases traveling in the same general direction and, surrounding but somewhat spaced away from the inner mantle.

theilength of and in close 11. The process of producing oxids of nii trogen, which comprises conducting gases comprising nitrogen in the form of a traveling mantle along the length of and in close proximity to .a.n electric arc, maintaining another mantle of gases traveling in the same general direction and surrounding but' somewhat spaced away from the inner mantle, and separatelv cooling the gases ofthe said mantles beyond the arc.

12-. The process ofproducing oxids of ni trogenflwhich "comprises conducting air in. the form of an'inclosing mantle or envelop along the length of and in close proximity to along arc, conducting another inclosingenvelop of air outside of and spacednaway from the inner mantle, and separately cooling the gases of the said mantles beyond the arc to a temperature belowthat at which substantial clecomposition of nitrogen oxid occurs. z

' In testimony whereof I have signed my name to this specification in the two subscribing witnesses. I

HANS GROHMAXN [\VitrisseSg' f i I RicHARuMinding OSCAR DEPNER. V

nesonve of 

